National Key Laboratory of Aerodynamic Design and Research

Fengcheng, China

National Key Laboratory of Aerodynamic Design and Research

Fengcheng, China

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Liu J.,National Key Laboratory of Aerodynamic Design and Research | Li J.,National Key Laboratory of Aerodynamic Design and Research | Jiang S.,No203 Research Institute Of China Ordnance Industries
Kongqi Donglixue Xuebao/Acta Aerodynamica Sinica | Year: 2015

In order to clarify dimple induced vortex structure, the fully developed flow between two plane, with a single dimple of classical depth to print diameter ratio of 0.2 placed on the below plane, is simulated with RANS in Fluent. The generation, development and breakdown of vortex structure are analyzed with the Zhang Hanxin's theory of vortex motion bifurcation along its axis. And the vortex induce effect after dimple is examined. It is found that the separation belong to a closed separation, in the separation line singular points distribute in spiral/saddle/spiral regularly. When the spiral separation point is generated, wall vorticity is converged to the spiral point and raised in spiral. So the tornado-like vortex is generated perpendicular to the wall. Symmetric tornado-like vortex is closed in symmetric plane, and a half vortex ring is generated. The half vortex ring experienced steady spiral rising, becoming unsteady in the viscous dissipation and viscous diffusion, and finally breakdown in the strong adverse pressure gradient. After the vortex breakdown, vorticity dispersed and weak longitudinal vortex is induced in the dimple wake which induces upwash in center and downwash in two sides. Rotating in the same direction with longitudinal vortex, induced by upwash in the dimple two sides, edge vortex assisted to enhance convection after dimple. © 2015, Editorial Office of ACTA AERODYNAMICA SINICA. All right reserved.


Nie S.-Y.,National Key Laboratory of Aerodynamic Design and Research | Gao Z.-H.,National Key Laboratory of Aerodynamic Design and Research | Huang J.-T.,National Key Laboratory of Aerodynamic Design and Research
Kongqi Donglixue Xuebao/Acta Aerodynamica Sinica | Year: 2012

While models based on the Boussinesq eddy-viscosity approximation provide different predictions for flows like shock and separated flow which differ greatly from corresponding measurements. A model based on full Reynolds-stress equation called Differential Reynolds Stress Models (DRSM) will be presented in this paper. Compressibility modification and an improved dissipation rate equation are accounted to improve a realizable model for real compressible flow, two groups of Closure Coefficients of SSG pressure strain model were tested. DRSM performs well when applying to the ONERA-M6-Wing at subsonic speeds at high angle of attack, especially the accuracy of the shock location and flow separation.


Xie Y.-J.,National Key Laboratory of Aerodynamic Design and Research | Ye Z.-Y.,National Key Laboratory of Aerodynamic Design and Research
Shiyan Liuti Lixue/Journal of Experiments in Fluid Mechanics | Year: 2010

Using the equipments in NF-3 wind tunnel which are specially designed to do plunging and pitching movement, NACA0012 airfoil is chosen to test with larger incidences. Its aerodynamic characteristics is investigated and analysed. And based on the solution of unsteady Reynolds-Averaged Navier-Stokes equations, the flow field around airfoil at high incidences are investigated under consideration of vibrations for wind-tunnel models. It is shown that the vibrations of the airfoil can cause large scale unsteady separated vortex shedding before the stall incidence, therefore, lead to lift decreasing and the stall appearing at some lower incidence than the steady meaning stall incidence. Concerning these two vibration modes, the effects of airfoil's pitching is serious than that of plunging. So the chord stiffness should be stronger in the process of model's design.


Li F.,National Key Laboratory of Aerodynamic Design and Research | Ye Z.,National Key Laboratory of Aerodynamic Design and Research | Gao C.,National Key Laboratory of Aerodynamic Design and Research
Lixue Xuebao/Chinese Journal of Theoretical and Applied Mechanics | Year: 2011

The new type tandem buoyancy-lifting airship, based on the NACA aerofoil, not only possesses considerable volume efficiency, but also the aerodynamic efficiency. In order to improve its aerodynamic efficiency farther, the optimum design for aerodynamic configuration of tandem airship is executed with the response surface methodology. Adopting the uniform experimental design method, taking the sweepback tandem airship as the basic configuration, axis and normal coordinate of back wing as the design variable, lift, drag and lift-drag ratio as the objective function, the second-order response surface optimization model of aerodynamic parameter has been constructed via CFD and response surface approximation theory. With the presented method, the optimization design is applied to lift-drag characteristic of tandem airship. The results indicate that the response surface methodology is effective, feasible and applicable for aerodynamic optimum design.


Song B.-F.,National Key Laboratory of Aerodynamic Design and Research | Ye Z.-Y.,National Key Laboratory of Aerodynamic Design and Research
Kongqi Donglixue Xuebao/Acta Aerodynamica Sinica | Year: 2011

The average aerodynamic characteristics of an oscillating wing in low speed flow have been investigated by solving the unsteady N-S equations and compared with that of the rigid wing. The structural modes and corresponding frequencies have been obtained by making use of the Finite Element Method (FEM). Assuming that the wing takes the first-order mode as its form of movement, the computations have been conducted at various angles of attack and amplitudes and the results have been studied carefully. The following conclusion has been reached: the average aerodynamic characteristics of the wing undergoing slight oscillations don't show any significant difference from that of the rigid wing, but with the growing amplitudes of the oscillations increasing differences between these two sets of results show up, showing growing decreases in the maximum lift coefficients and stall attacks. The results presented in this paper have partly explained the fact that the maximum lift coefficient and stall attack in wind tunnel tests are usually smaller than the CFD results where the wing is considered rigid.


Xu L.,National Key Laboratory of Aerodynamic Design and Research | Wang G.,National Key Laboratory of Aerodynamic Design and Research | Wu J.,National Key Laboratory of Aerodynamic Design and Research | Ye Z.,National Key Laboratory of Aerodynamic Design and Research
Kongqi Donglixue Xuebao/Acta Aerodynamica Sinica | Year: 2014

Focused on the quantification of the uncertainties of areodynamics performance of airfoils with respect to geometry error, with a set of CFD program based on finite volume algorithm solving the Reynolds-Averaged Navier-Stokes equations with S-A turbulent model, adopting automatic differentiation method to reform the program simultaniously, all kinds of sensitive derivatives, uncertainties of all kinds of aerodynamic coefficients and pressure coefficients distribution resulting from geometry error could be obtained in one course of computation. As the computational results show, even if the geometry error is only 63 microns (while the length of chord is 1 meter), the pressure distribution of the walls could be influenced obviously with uncertainty quantity reaching 0.312 (taking dynamic pressure of the flow as reference) for an airfois in transonic flow, moreover, pressure attached to the place where shock wave stationed bears peak uncertainty. the results of method of automatic differentiation account for the dispersity of results of numeric simulations and wind tunnel experiments well.


Zhang Q.,Northwestern Polytechnical University | Zhang Q.,National Key Laboratory of Aerodynamic Design and Research | Ye Z.-Y.,Northwestern Polytechnical University | Ye Z.-Y.,National Key Laboratory of Aerodynamic Design and Research
Journal of Aircraft | Year: 2015

A study was conducted to generate a hybrid unstructured computational volume mesh, which was a prism element in boundary layer and a tetrahedron element in the other fluid zone. To simulate the complex vortices on the suction side of the delta wing as accurately as possible, mesh elements in the suction zone were refined adequately. Pressure far-field conditions were applied at far-field boundaries, no slip conditions were used at the wall, and it is assumed that the wall was rigid. A comparison was made between the computational and experimental results of the pressure coefficient of the VFE-2 surface to validate the current computational method.


Han Z.-H.,Northwestern Polytechnical University | Han Z.-H.,National Key Laboratory of Aerodynamic Design and Research | Zhang K.-S.,Northwestern Polytechnical University | Zhang K.-S.,National Key Laboratory of Aerodynamic Design and Research | And 4 more authors.
Journal of Aircraft | Year: 2010

An efficient method based on the surrogate-management framework has been excised to optimize the actuation parameters of active flow control over an airfoil via a synthetic jet. In this approach, sample points are chosen by the design of experiments method, and approximation models are built based on the sampled data obtained from unsteady Reynolds-averaged Navier-Stokes simulations. The accuracy of these approximation models is evaluated at some test points by comparing the approximated values with the accurate values obtained from unsteady Reynolds-averaged Navier-Stokes simulations. Three types of approximation models (quadratic response-surface model, kriging model, and radial-basis-function neutral network) are built from the same data set. The model with highest accuracy is chosen as the surrogate model to be used to replace the unsteady Reynolds-averaged Navier- Stokes analysis during optimization. The optimization objective is to maximize the lift coefficient of a NACA 0015 airfoil at given angles of attack (14 to 22°), with the jet momentum coefficient, nondimensional frequency, and jet angle being the design variables. The surrogate model is coupled with a simulated annealing genetic algorithm optimizer to efficiently obtain the global optimum. As a result of the optimization process, the lift coefficient at an angle of attack of 16° is increased by 16.9% and the corresponding drag is decreased by 13.4% with respect to the initial controlled flow. It is preliminarily shown that the presented method is efficient and applicable for optimization of active flow control via a synthetic jet.


Li F.,National Key Laboratory of Aerodynamic Design and Research | Ye Z.-Y.,National Key Laboratory of Aerodynamic Design and Research | Gao C.,National Key Laboratory of Aerodynamic Design and Research
Gongcheng Lixue/Engineering Mechanics | Year: 2013

It has important scientific value to develop the buoyancy-lifting airship with higher aerodynamic efficiency. The new type tandem buoyancy-lifting airship, based on the NACA aerofoil, has considerable volume efficiency and aerodynamic efficiency. In order to examine the utility value and economy benefit at the design load condition, the buoyancy-lifting characteristics of tandem configuration in stratospheric platform are studied. Furthermore, its total performance and technical parameters are analyzed. Tandem buoyancy-lifting airship has excellent performance and utility value. As a result, its deadweight is decreased and payload and specific productivity are increased with smaller cost. Therefore, it is not advisable to overly pursue the minimization of drag. Contrarily, we need to seek a compromise between low drag and small dimension.


Xia M.,National Key Laboratory of Aerodynamic Design and Research | Li D.,National Key Laboratory of Aerodynamic Design and Research | Song B.-F.,National Key Laboratory of Aerodynamic Design and Research | Ye R.,National Key Laboratory of Aerodynamic Design and Research
Kongqi Donglixue Xuebao/Acta Aerodynamica Sinica | Year: 2010

RANS/LES hybrid methods based on S-A model is presented here to simulate the separated flow of the slender under the influence of pitching oscillation at high angle of attack. The location and strength of separated vortex, flow field and pressure distribution on the surface were observed and analyzed. It is found that, the pitching oscillation at fixed frequency has strong control ability to the slender body at high angles of attack, and it would change the construction of flow field, the asymmetrical flow was restrained and tends to symmetrical flow.

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